Researchers already knew (and were baffled as to why) Marin County's women experienced higher rates of breast cancer, but a new study using census tract data from the Public Health Institute's California Breast Cancer Mapping Project found an elevated incidence of breast cancer in Sonoma, Napa, Solano and Contra Costa Counties. Some South Bay communities, including San Mateo County, northern Santa Clara and southern Alameda Counties, also have higher than average rates.

What's going on? Scientists still aren't sure, but at least now they know it probably has less to do with Marin in particular (darn, there goes my cancer-causing high-end yoga pants theory) and more to do with the general environment up north.